Myo-Inositol Intake during Pregnancy Alleviates Inflammation and Oxidative Stress in Sows and Improves Skeletal Muscle Development Characteristics in Offspring.

BACKGROUND

Skeletal muscle is essential for exercise and maintaining metabolic homeostasis. Myo-inositol (INS), the main isomer of inositol, has been shown to enhance glucose metabolism and skeletal muscle growth in fish. However, its effect on skeletal muscle development in mammals remains unclear.

OBJECTIVES

This research seeks to investigate the positive impacts of maternal INS intake during gestation on skeletal muscle development in the offspring using pig models.

METHODS

Random allocation was performed to distribute 45 parity-matched Landrace × Yorkshire sows across 3 treatment arms: control, 0.15% INS, and 0.3% INS supplementation groups from D30 of pregnancy until farrowing. The levels of inflammation and oxidative stress in the serum (n = 8) and the composition of the gut microbiota (n = 6) of pregnant sows were evaluated. On postnatal day 1, 6 male piglets (n = 6) were selected from each of 6 litters in the control group and the 0.3% INS group. The mRNA and protein levels of key genes involved in skeletal muscle development and fiber-type composition were measured. RNA-seq analysis was then performed using the skeletal muscle of piglets. Data were analyzed using 1-way analysis of variance followed by Tukey's multiple comparison test or an unpaired 2-tailed Student's t-test.

RESULTS

Dietary INS supplementation reduced inflammatory markers on D50 of pregnancy, alleviated oxidative stress in sows, and decreased the number of piglets with low birth weight by ∼60% (P = 0.01). On D50 of pregnancy, dietary supplementation with 0.3% INS reduced the relative abundance of Firmicutes from 72.92% to 60.17%, while increasing the abundance of beneficial fecal microbes in sows, such as Bacteroidetes, Fibrobacterota, Unclassified_f_Lachnospiraceae, and Prevotellaceae_NK3B31_group. Notably, maternal 0.3% INS intake increased paired box 7 protein level by 88.90% (P = 0.05) and induced muscle-fiber type transition from glycolytic to oxidative fibers in the skeletal muscle of piglets at postnatal day 1. This was evidenced by a 50.95% increase in the mRNA level of myosin heavy chain (MyHC) Ⅱa (P < 0.05) and a 55.50% decrease in the protein level of fast MyHC (P < 0.01). Transcriptomic analysis further revealed that maternal intake of 0.3% INS regulated signaling pathways associated with skeletal muscle development, such as mitogen-activated protein kinase, Notch, and Wnt.

CONCLUSIONS

INS intake was beneficial for the inflammatory and oxidative status of pregnant sows and further improved skeletal muscle development characteristics in the offspring.